Telephone-exchange system



NOV. 11, 1930. EMHAGUE 1,781,385

TELEPHONE EXCHANGE SYSTEM Filed March 30, 1929 ATTQH EY Patented Nov. 11, 1930 arana" oremg I i i t 1 i i ALFRED E. HAGUE, OFQWEST ORANGE, NEW JERSEY, ASSIGNOR T BELL TELEPHONE LABORATORIES, IKCORPORATED, OF N YORK i TELEPHONE-EX EW YORK, 1\T.-Y., A CORPORATION OF NEWH cannon SYSTEM Application filed March 30, 1-929. SerialNou35L203.

This invention relates to telephone systems: and more particularly to improvements in party linemessage registration.

The object is touenable the performance g of a more positive and reliabletest of party lines to identify the stationoriginating the call. i

According to onefeature of'this invention uni-directional current-carrying devices are a; leemployed atthe stations on a party line in combination with an unbalanced condition of the tWo sides of theline to-serve as an'identification of the calling line.

According to: anotlier feature of the inven- H5315 tion polarized ditferentialyrelays are employed in testing a calling line to determine ywivhich party has originated the call. By :applying to the line'sources of; potential-of a different polarities the operation of thertest 1 i relays indicates which station'is the calling station and controls the selection of thecorresponding message-register i The-drawing sho-u sthe invention applied to a four-party line inan automatic telephone system. a i

Fig; 1 illustrates: diagrammatically a fourpartyline 9 \Vl'llCh isconnected to a set ofterminalsin a line finder bank, a line finder LF which has accessto this loank' for finding the 3s lineivhena call is originatedhy one of the r stations, anda selector '5) .Which is associated with the linerfinder LE for extending "the calling line. 1 a "V The party line 9 is T shown with four subscriber stations A B,'.G and D. The station A is: provided With a'uni directional currentcarrying device 1 andarelayfi, connected in series between onegofthe switchhook contacts and ground. A current flows through theuni-direction'al current-carrying device 1 and through the Winding of relayw5 only P. wh n an electromotive iorceofa certain poline. "The station Bis similarly equipped 4.3; \Jlt'ih'it uni-directional current-carrying de- 7 I =vice 2 and a relay 6, so connected that a current-flows through the relay 6 only when an electromotive force of the same magnitude hut opposite polarity is impressed upon the :linej The stationsGand D are equippedwvith ity and magnitude is impressed upon the devices 3Hand 4t andvwith relays 7 and 8; connected similarly to: the devices and relays at stations A and B, respectively. Theoperation of either ofrelays 5 and 8 opens the circuit over the tip side of theline 9 andthe;

operation of either of relays (Sand 7 opens the circuit over the ring sideof the line 9. The opening of either the tip or ring side of the line makes possihlethe identification of the callingstation by the use of differene; tially-Wound polarized vtesting relays at the central oifice.

,In Fig.2 is shown.anaalternativearrangement of the stations on a four-party; line. a Stations E, F, G, and H are equipped with uni-directionalcurrentcarrying devices 62, 63, 64 and65 similar to those with which stations A, B, C and Dare equipped, but the relays' for openingeither theitipy'or ringsides ofthe line, :during the identification test oil; the line, areomitted. [Bythe removal of the receiverat either of stations E and H the tip side of the line is connected through the a transmitter and one Winding of the induction coilto the device 62 or 65, but the ring side of the line is connected directlyto. the device 62 or 65; by theremoval of the receiver at either of stations F and G, the ringside of the line is connected through the transmitter and oneWinding-of the induction coil to the device 63 or G iwhi-le the tip side is connected directly to the device 63 or 64:. This arrangement secures sufficient unbalan cebetween the two sides of the line to selectively operatethe differentially WOUnCl polarized testing relaysw rat the central ofiicewvhentheline is tested to .dBtGI1J1i118=WlllGh is the calling station. :It is therefore not necessary toprovide i any. at each station; to* accentu ate the unbalance by opening one side oftheline during the identi" fication test as is the casewhen the stations are connected as shown in Fig. 1.

The uni-directional current-carrying devices at stations A, B, C, and D and at stationsE,,F,G and H are shown as space discharge tubes and may be similar to the one illustrated in the application of F. Gray, Se-

wrial NoLt98,658, filed March 31, 1926. Other types: ofuni-directional current-carrying do;

43' the otherofjitswindingstothe ,otheriside of vices might beused instead of space discharge 7 tubes. c

' nates in a bank which is accessible to the line 7 finder switch LF; T he line finder LFi-s illustrated diagrammatically by the brushes 10 At the central ofhce the party line termito 16 inclusive and is connected directly to a v No. 1,589,402, issued une22,1996f Control; 1 and operating circuits: for aselector switch of this character arealso' shown-inthe'patent toStearn et' al,No'.'1,395,977,issued 'Novemf 1 selector switch S having brushes28, 29; and

her 1, 1921; The switcheslLF'a'nd "S may be of the'panel type and the sequence switch-31 which controls the circuitchange's may be siinilar tothat illustrated fin the Kopp and "Stear-n' patents mentioned above. "'The1nessage registers 17,18, 19 and, 20 are respectively individual tostations A, B, C and D 1 -and are connected 'to'terininals :in the line finder bank which are coinpani'on to the line terminals. The meansfor determiningfwhich I of the stations has originated acallincludes' above mentioned, test or the line 9, to identity the rotary stepping switch having-a stepping v testing relay 23, and, with test control relay 40 operated, through the contacts of relay40 and brushes 10 and 11 015 the line finders-LE" j to both sides of the line 9. The windings or V testingrelay 21 are "difierentially connected so that there'lay will not operate when the current "through one of'its flwindings to one also connected differentially the testing 7 v magnet 32, the oppositely poled sources of testing potential 54 and 55, the testing control relay 40, and thel difiere'ntially The circuit/is .arrangedto successively conrespectively through both winnings or; {the sideof the line is equal to the current through the line. The windings of'testinggrelayh are circuit so thatirelay 23 will, not 'operatewhen thecurrent through oneor' its windings to one 5 sideof the line'is' equal-t0 the current through the other of'its windings to the other side-or 5. the line. Each ofthese testingre'lays isapo- 'la'rizedso that it will notoperate-even though there is a surhcientxdillerence instrength be -tweenthe currents 7 through its windin'gs unless the winding through whichthe currentis the strongerlispolcdcin the same, direction .as thecurre'ntQ T0 illustrate,' when tlie positivesource-of testing potential is connected hrough the windingstof test rel jS 21 and '23 to the line '9, relay '21 operatesif' the; current flowing through itslerthand winding is LStrOngerthanthe current through its right 'ghand-w1nd1ng,the'd1fference 1n strength'being I ound' polarized testing relays 21 a d 23 lead 66."

sufi icient to cause operation, andrelay 23- operates if the current flowing through its right hand winding is stronger than thecurrent I Y through itsleft hand winding. AIKLNVllQH' the negative source'or testing potential is connected throughthe windings of test relays 21 and 23to the'line 9,:relay 21'operates 1f 1 the currentfiowing through its right hand Wind ng stronger than the current through its left hand winding the" dlfi'erence 1n the line finder LF the line 9 has been ex.-

tended to selector S, that the impulse transmitter: atthe calling station A liasbeen rnacalled line in register sender at the central office,and that the register sender has'controlled thejselector S vand the succeeding switches to 'extend-igthe connection. to the called subscrib'ers linein the usualfnianner,

.strength being sufi icient to, cause reparation, and-relay23 operates f the current flowing 1 s5 a nipulated to set up. the designation of the p as is fully described in the- Stearnip'atent the calling station, is" initiated" after the called subscriber hasianswered and will be described in detail. I r j r e x l/Vhe'nj the called. subscriber answers the eall thedirection' of'cur'rent flow over the trunk, withwhose teri'ninalsthebIuShes-QS 7 10a versed "therebycausing the operation or the polarized supervisoryrelay41. At this time V the sequence switch 31 has advanced to some andj29 of selector Sane in contact, is reposition, such as position 13, in 'whichthe swltch rema ns. during conversationw As soon, afterithe relay 41'operatesfas'theinteris completed from battery through the wind- 48,;c0ntacts of sequence switch 1 spring. 49,

"rm-peer 48 closes its upper contact, a circuit' lead 66, contacts of relay 4L1, f'andthrough the contacts of sequence-switchsprings 46 and 47, to ground. Relay 39 operates and looks through its left:v hand contacts and through the contacts Toff sequence switch 1 springs 50j andf49; to ground. on lead- 66, -As' so0n 7 after relay -39 hasjoperated as the interrupter 48closes. its lowercontact,

a circnitis' closed frombattery' through the winding of relay 40,"backcontact ne. lay38, contact of sequence switch spring 4 4, '7 front contact andrighthand armature-or fic lay 39, lower contactofinterruptert8, 'conjtacts of sequence switchspring 5&9, to ground- I on lead66. Relay Oiope'rates'in this circuitjl" and is locked through itsouterupper arnia' 'ture .andpfront contact tofithelgroundg on f g The brushes and doftheirotary stepping. switch are "now advanced by the "alternate operationan'd releaseof the stepping magnet. 32 to control the testing of the "line 9. With thebrushesin any one of positions 1 to 5 inclusive, position 1 being the normal position, a circuit is closed, after relay has operated, through the winding of stepping magnet 32 each time the interrupter closes its contacts. This circuit may be traced from battery, through the winding of magnet 32, brush 34 in any one of positions 1 to 5 inclusive, the front contact and middle lower armature of relay 40, and

through the contactsof interrupter 45, to

grounds. The release of the magnet 32 each time this circuit is opened at the contacts of interrupter 45 advances the brushes one step i at a time from position 1 to position 6. After the brushesare advancedbeyond position 5 the magnet 32 is no longer under the control of interrupter 45. i

WVith the stepping switch in position 2, a circuit is closed from battery, through the winding of relay 37,brush 35 in position 2, lead 27 and through the contacts of sequence switch springs46 and47,'to ground. Relay. 37=operates in this circuit andlocks through its front contact and right hand armatureto ground on lead 27. Theo'peration of relay 37 prepares the circuit for operating the calling subscribers message register after the calling subscriber has released the connection.

With the stepping switch in position 2, a

' circuitis closedfrom thepositive source of testing potential 54, through resistance lamp 56,'brush36 in position 2, both windings of relay 21, both windings of relay 23, front contacts 5 and inner armatures of relay 40,

i and through brusheslO and 11, to the tip and ring sides "respectively of the'line 9.

The device 1 at station A is so connected that there is no current in this circuit and neither test relay 21 nor test relay 23 opcrates.

No further operation takes place while the stepping switch ,is in position 3 but when-the switch has: advanced to position 4 the negative source of testing potential is connected'through resistance lamp 57 and brush 36 in position 4, through the windings of test relays 21 and 23to the tip and ring sides of line 9. Current in this circuit, over both sides of the line through the uni-directional current-carrying device 1 and the winding of relay5 to ground, operates relay 5. The operation of relay 5 opens the circuit over the tip side of the line 9 thereby creating an unbalanced condition between the two sides of the line so as to'cause the operation of testrelay 23. The operation of relay 23 closes an obvious. circuit for 0pcrating relay 24. Relay 24 locksthrough its irontzcontact and its upper inner armature to ground on lead 27.

No further operation takes place until the brushes of thestepping switch-are advanced to position 6 at which time a circuit is closed from battery, through the winding of relay 38, brush 35 in position 6, to ground on'lead 27. Relay 38 operates in this circuit and locksthrough its front contact and inner right hand armature to ground on leadi27. The operation of relay 38 connects ground through its front contact and left hand inner armature, armature and back contact of stepping magnet 32, brush 33 in pos1t1on 6, and

throughthe windingof stepping magnet 32,

to battery." The operation of magnet 32 opens its own operating circuit and its release advances the brushes to position 7. Since the terminals from 6 to 2Tinclusive, with which brush33 is'associated, are all connected together, stepping magnet 32 continues toopcrate and release and thus advance the brushes until they have reached position 1,.

their normal position. The apparatusre mains in this condition during conversatlon.

When thecalled subscriber replaceshis receiver on the switchhook relay 41 releases and sequence switch 31 is advanced from the talking position to a subsequent position such as position 17 inwhich the message register 17 oi? the calling station A is to be operated.

The release of relay 41 opens the holding circuitfor relay 39 and this latter relay releases.

Relays '37 and 38 are now held in a circuit through theirwindings and lockmg contacts over lead 27, through theback contactand right hand armature of relay 39, brush 33 in position 1, contact ofstepping magnet 32, left hand 11111131 armature and front contact of relay 38, toground.

Whilethesequence switch 31 isadvancing from position 15 to position 17, a circuit is closed from battery, through resistance 67,

theleft hand armature and front contact of relay 37, contacts of sequence switch spring 51, front contact an'dlett hand outer armature of relay 38,lower armature and back contact ofrelay 26, lead 68, front contact and upper outer armature of relay 24, lower armature and back contact of relay 25, brush 13, and through the winding of message register 17, to ground. The message register 17 is operated in this circuit, thereby charging the subscriber at station A. for the call. When the sequence switch reaches position 17 and as soon thereafter as interrupter 59 closes its contacts, a circuit completed from battery,

I Jlay'22; Relay 22 looks through its tront con- "tact and upper inner armature, toground on lead 27. Later when the sequence switch 31is.

- advancing from position 15 toposition 17,

i V 25 the metering circuit isclosed from battery Floater-when the sequence g o from position 1 to position 17, aineterl a rough: s stance as, hereinbe'i ore traced to leadcr i RCA

manner such as explained in the patent'to. 3 'Kopp mentioned above. v V

Assume next that the call is initiated by ug t efr t ntact a d mperm er armature of relay 24, lower armature and V front contact vof relay 25 brush 15, and

' the subscriber at station B. In this case when,

the positive source of testing potential 54*, is I connected'to the tip and ring sides of line 9, neithe1' ,of"test relays 21' or 23 is operated since there isno current through theuni-directional' current-carryingedevice 2 and .re-' -lay 6. When the stepping switch has ad-T vanced to position 4 the test circuit is closed" vfrom the negative source of potential 55,

through the windings'ot' the teistrelays 21 and 23, tip .and ring sides of line 9, through the, device 2. and relay-6, to ground; Relay f 6 operates, thereby opening the'ring side ofvthe line 9 to create an unbalance between the twosidesof theline which causes the operavtion oftest relay- 21. The operation o1 relay '21 closes anobvious circuit-for operating rethrough the "resistance 67, as hereinbefore traced ,to lead v68', through the front contact and upper outer armature of relay 22, upper outer armatureand back contact of relay25, .brush 14, and through the-winding of message register 18 ,toground. The message 1 register '18 is operated in this circuit thereby charging: the: subscriber atstationB for the.

I i call; ;,-c I

1 Assume next thatthe call is initiated. by

V the subscriber at stat-ionC, Inthis case-when the stepping switch has advanced to position,

2' and thepo'sitive source of testing potential. E lis 'connected'to the tip and 'ringsides of l I line9, relay 7 isoperatedby the current over both sides of the line, through the unidirec *t ional current-carrying device 3 and relay 7 v to ground :Th'ecperation of relay/(opens th'ec rcuit over the ring side of the line, theresidesot thelineto cause theoperation of by creating'an unbalance between the two,

through the winding of Inessageregister 19, to ground. The register 19 isoperated in this circuit thereby charging the subscriber at stat-ion Ctjorthecalh, c 1 V e Assume, finally, thatthecall is initiated by the subscriber at station D. W hen theposi- 'isadvancing from position fto position-17 V I after the calling; subscr1ber has released the:-

fore traced torlead 68, throughthefront con tive sour ce of testing potential 54: is con-r nected through the windings of the testing relays 21v and 23 to the tip and ring sides of the line 9, relay 8 operates thereby opening "the circuit over the tip. side of the line, The

same ground and'when the sequence switch 81 90 connection, theinetering circuit iscl'osed trom battery, through res1stance 67, as here1nbetactand' upper outer armature of relay22,

upper outer armature and front contact of relay 25,:brush'16, and-through the winding i of message register 20, to ground:- The mesm 'sage register is operated in; this circuit thereby charging the 'Dforthecall; na In case subscribers at more than one ofthe subscriber'iat station 'stationsatternpt to originate'a call at the same l testing relay.;23. 'The operation of'relay 23, V

1 causes the operation/of relay 2% whichf'l ocl s -to ground on lead 27." VVhent-he"stepping reiay'25, trontcontact and lower inner arrna 11116 of relay; 24, brush '35 in position 3', -to our d on lead 27; -.Relay-25 locks through its ont conta'ct and upper inner armature, to oun'd onlead27i When the negative source 1 the windin s fofthe testrela s 21 and 23 to is no; current through thedevice3 and'relay 7 b I 0 a g ci cu t is closed from battery,

switch has advanced topositi on 3 a circuit" ;isclosedfrorn battery,-through the winding off of testing potential is connected through;

the'line9,the switch'beinginpositionhthereg Qandfneitherot thetestrelays is operated;

switch 311s advanc-jtime both of the testingrelays 2,1 and23 will have been operated by current in the test c'ir I V cuitas hereinheforedescribed. Relays 22 and 2-4:;will also have beenf operated and when the stepping switch has advanced to 'position 5a circuit is closed from battery',-through the winding of relay 26,'f front,contact and lower outerfarinature of relay 22,-lower outer arnia- -tureand frontgcontaet of relay 24,,brush .35

:in position:5, to'ground at-leade27s Relay 26 mature and front contact otrel'ay 37,0ontacts {of sequence switch spring 5-51,; vfront contact and left-hand outer armature of relay 38 and V "throughthe. lower armature and front conf l V tact or relay26, tothe alarm circuit 58, I This jot therinessage registers and operates' a suit 1able;jalarrn device If neither ottest relays 21 V o :and;23 has been operated during l-theitests- V operates in this cireuit and'loclrsthroughits- I Vfront contact andupperarniature to sarne ground; .The' operationof relay' 26 connects battery, through resistance 67, left handararrangeinentl prevents the 'operation of, any

d While the st ppeeese; is inv r s time e ethecircu a for Op rariegi iayee is closed throughthebackfcontacts otrelays '130 22 and 24 and through brush 35 in position 5 to ground on lead 27, and the consequent op eration of relay 26 closes the alarm circuit as just described.

While the invention has been shown in connection with a telephone system employing panel switches, it is to be understood that it may be embodied in systems of other types.

What is claimed is: 1. In a telephone system, a line having a plurality of subscribers stations, one of which is a eallingstation, means at each of said stations for creating an unbalanced condition of the two sides of the line, and means including differentially-wound polarized relays for testing. the line to determine the calling station.

2. In a telephone system, a line having a plurality of subscribers stations, one of which is a calling station, means including a uni-directional current-carrying device at plurality of subscribers stations, one of which is a calling station, means including a uni-directional current-carrying device at each of said stations for creating an unbalanced condition of the two sides of the line, and means including difierentiallywound polarized relays for testing the line to determine the calling station.

l. In a telephone system, a line, a plurality of subscribers stations permanently connected to said line, means at said stations for rendering each of them distinguishable from the others when a call is originated at one of said stations, and means including difierentially-wound polarized testing relays for testing the line to determined which of said stations is the calling station.

5. In a telephone system, a line, a plurality of subscribers stations permanently connected to said line, one of said stations being a calling station, a receiver and a re ceiver hook at said calling station, a unidirectional current-carrying device at said calling station for connecting ground to both sides of said line when said receiver is removed :Erom said hook, and means including polarized differentially-wound testing relays for determining which-of said plurality of stations is said calling station.

6. In a telephonesystem, a line having a plurality of subscribers stations, one of which is a calling station, means at said calling station for rendering said calling station distinguishable from the other stations of said line, a positive source of testing potential, a negative a source of testing potential, polarized differentially-wound relays, and means for successively connecting each of said sources of testing potential to the windings of said relays and through said windings to said line to determine which of said plurality of stations is the calling station.

7. In a telephone system, a line having a plurality of subscribers stations permanently connected thereto, a call originated at one of said stations, means for testing said line to determine which of said stationshas originated the call, and a uni-directional currentcarrying device at said calling station effective upon the initiation of said call to connect said line to ground, and means actuated by current through said device to disconnect one side of said line from said device.

In witness whereof, I hereunto subscribe my name this 29th day of March, 1929.

ALFRED E. HAGUE. 

